Patent GB-1350298-A (GB)
Title: Process and apparatus for continuous production of synthetic plastics hollow or solid sectional elements
IPC: B29C70/50
Filed: 1971-06-24
Abstract: 1350298 Laminates; moulding profiles R LUPERT 24 June 1971 [25 June 1970] 29641/71 Headings B5N and B5A [Also in Division F2] Hollow or solid sectional elements of plastics material reinforced by fibres are produced by applying to an elongate backing foil the width of which corresponds at least approximately to the periphery of the sectional element to be produced, liquid synthetic resin and a fibre layer of approximately the same width as the backing foil, to form a strip of laminated material which is then passed longitudinally through a forming means including a forming plate which causes at least part of the width of the laminate strip to be deflected from the plane of the strip, the deflection increasing as the material passes through the forming plate, the strip being pressed against the forming means by the application of a fluid pressure difference between the two sides of the strip, and then polymerizing or gelling and fully hardening the synthetic resin. In Fig. 1 backing foil 2, e.g. of siliconized paper or cellophane (registered Trade Mark) foil is fed from stand 1 over deflecting rollers 4 to coating head 5 where a plastics layer, e.g. unsaturated polyester resin, is applied, suction hood 6 removing deleterious dust and heating duct 7 producing polymerization of the plastics material. A mat or random web 10 of glass fibres is applied between two resin injection heads 8 and 9, venting rollers 11 under suction hood 12 ensuring venting of the still unhardened laminate which is fed to forming plate 14 and prehardening duct 13 where the sectional element is calibrated and hardened. Reinforcing inserts 16 e.g. impregnated corrugated cardboard are introduced prior to entry of the sectional element into final hardening duct 15 from which it is drawn off by conveyer 17, cut into desired lengths with saw 18 and discharged at shoot 19. Backing foil 2 may be drawn off after formation of the sectional element. Other reinforcing materials include fibre webs, fibre type, flocculate and string type fibre layers of jute, nylon, sisal or flax. Forming plate 14, which may be of metal or plastics material having perforations so that suction may be applied and may be heated or cooled, is of straight line cross-sectional contour on the entry side of the backing foil and the succeeding cross-sectional contours develop continuously into the outer peripheral contour of the sectional element to be produced. Calibration and pre-hardening zone 13 may also be perforated so that suction may be applied, or if peripherally-closed sectional elements are being produced over pressure. If open sectional elements are being produced pressure application members, e.g. rollers, journals or rails, may be applied against the inside of the sectional element to render possible a regular edge construction. When peripherally closed sectional elements are produced two calibration cores fixed to one another by cables or chains may be provided in zone 13 and an overpressure produced or foamed material introduced. Decorative surface foils may be used.